Regulation of normal cell cycle progression by flavin-containing oxidases

• Published in: Oncogene Vol. 27; no. 1; pp. 20 - 31
• Main Authors: Venkatachalam, P, de Toledo, S M, Pandey, B N, Tephly, L A, Carter, A B, Little, J B, Spitz, D R, Azzam, E I
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 03.01.2008; Nature Publishing; Nature Publishing Group
• Subjects: Active oxygen; Animals; Apoptosis; Biochemistry; Biological and medical sciences; Cancer; Cell Biology; Cell culture; Cell cycle; Cell Cycle - drug effects; Cell Cycle - physiology; Cell cycle, cell proliferation; Cell Line; Cell physiology; Cell Survival - drug effects; Cell Survival - physiology; Cell transformation and carcinogenesis. Action of oncogenes and antioncogenes; Cells, Cultured; Fibroblasts - cytology; Fibroblasts - drug effects; Fibroblasts - enzymology; Flavins - metabolism; Flavins - physiology; Fundamental and applied biological sciences. Psychology; Genetic aspects; Genetics; Growth Inhibitors - pharmacology; Human Genetics; Humans; Internal Medicine; Medicine; Medicine & Public Health; Membrane Potentials - drug effects; Membrane Potentials - physiology; Mice; Mice, Inbred C3H; Mitochondrial Proteins - metabolism; Mitochondrial Proteins - physiology; Molecular and cellular biology; NADPH Oxidases - antagonists & inhibitors; NADPH Oxidases - metabolism; NADPH Oxidases - physiology; Oncology; Onium Compounds - pharmacology; original-article; Oxidases; Oxidation-Reduction; Physiological aspects; Signal transduction; Signal Transduction - drug effects; Signal Transduction - physiology; United States; flavin-containing oxidases; checkpoint; p38; reactive oxygen species; checkpoint/G; cyclin D1; NAD(P)H oxidase/nitric oxide synthase; ATM/p53/p21; cellular proliferation/G; Cell proliferation; Enzyme; CDKN1A Gene; Oxidase; NAD(P)H oxidase/ nitric oxide synthase; Cyclin D1; Normal; cellular proliferation/G1 checkpoint/G2 checkpoint; Carcinogenesis; ATM/p53/ p21Waf1/p38MAPK/cyclin D1; Nitric-oxide synthase; Free radical; Regulation(control); TP53 Gene; Cell cycle; p38 Mitogen activated protein kinase; Oxidoreductases; Control point; Tumor suppressor gene
• ISSN: 0950-9232; 1476-5594
• DOI: 10.1038/sj.onc.1210634

Mechanisms underlying the role of reactive oxygen species (ROS) generated by flavin-containing oxidases in regulating cell cycle progression were examined in human and rodent fibroblasts. Incubation of confluent cell cultures with nontoxic/nonclastogenic concentrations of the flavoprotein inhibitor, diphenyleneiodonium (DPI), reduced nicotinamide adenine dinucleotide phosphate (NAD(P)H) oxidase activity and basal ROS levels, but increased proteolysis of cyclin D1, p21 Waf1 and phospho-p38 MAPK . When these cells were allowed to proliferate by subculture in DPI-free medium, an extensive G 1 delay was observed with concomitant activation of p53/p21 Waf1 signaling and reduced phosphorylation of mitogen-activated kinases. Compensation for decreased oxidant generation by simultaneous exposure to DPI and nontoxic doses of the ROS generators, γ -radiation or t -butyl-hydroperoxide, attenuated the G 1 delay. Whereas the DPI-induced G 1 checkpoint was completely dependent on PHOX91 , ATM and WAF1 , it was only partially dependent on P53 . Interestingly, G 1 to S progression was not affected when another flavin-containing enzyme, nitric oxide synthase, was inhibited nor was it associated with changes in mitochondrial membrane potential. Proliferating cells treated with DPI also experienced a significant but attenuated delay in G 2 . We propose that ATM performs a critical function in mediating normal cellular proliferation that is regulated by nonphagocytic NAD(P)H oxidase enzymes activity, which may serve as a novel target for arresting cancer cells in G 1 .